Mutant Gene Stops At-Risk People From Getting Alzheimer's: Could It Lead to Treatment?

The APOE4 gene is the most powerful genetic factor driving a person's risk for developing late-onset Alzheimer's disease.

"It probably increases your risk two or threefold if you have one APOE4 copy, and if you have two APOE4 copies, it probably increases your risk about tenfold," said Dr. Michael Greicius, a professor of neurology at Stanford Medicine.

But that story just became a little more complicated -- in a way that could potentially save the brains of millions who've inherited the APOE4 gene.

An international research team led by Greicius has discovered a rare mutation that actually negates the Alzheimer's risk posed by the APOE4 gene.

The R251G variant changes just a single amino acid in the apolipoprotein E (APOE) gene, but that simple alteration appears to neutralize the Alzheimer's risk normally caused by APOE4, researchers said.

Unlike most people with APOE4, people with the R251G mutation have no increased risk of developing Alzheimer's, according to a Stanford news release.

"Maybe 1 in 1,000 people who carry that high-risk gene also carry on the same copy of the...